Reconciliations of capital expenditures (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Reconciliation of Capital expenditures
Segment Reporting Information, Expenditure for Additions Long-Lived Assets	$ 587	$ 493	$ 1,687	$ 1,491
Operating Segments | Reportable Segments
Reconciliation of Capital expenditures
Segment Reporting Information, Expenditure for Additions Long-Lived Assets	526	427	1,460	1,262
Operating Segments | Reportable Segments | Construction Industries
Reconciliation of Capital expenditures
Segment Reporting Information, Expenditure for Additions Long-Lived Assets	56	37	120	85
Operating Segments | Reportable Segments | Resource Industries
Reconciliation of Capital expenditures
Segment Reporting Information, Expenditure for Additions Long-Lived Assets	44	10	101	63
Operating Segments | Reportable Segments | Energy & Transportation
Reconciliation of Capital expenditures
Segment Reporting Information, Expenditure for Additions Long-Lived Assets	115	100	339	331
Operating Segments | Reportable Segments | Financial Products Segment
Reconciliation of Capital expenditures
Segment Reporting Information, Expenditure for Additions Long-Lived Assets	311	280	900	783
Intersegment Eliminations | All Other operating segments
Reconciliation of Capital expenditures
Segment Reporting Information, Expenditure for Additions Long-Lived Assets	59	46	106	84
Intersegment Eliminations | Cost Centers
Reconciliation of Capital expenditures
Segment Reporting Information, Expenditure for Additions Long-Lived Assets	15	8	34	23
Intersegment Eliminations | Timing
Reconciliation of Capital expenditures
Segment Reporting Information, Expenditure for Additions Long-Lived Assets	(13)	1	96	147
Intersegment Eliminations | Other
Reconciliation of Capital expenditures
Segment Reporting Information, Expenditure for Additions Long-Lived Assets	$ 0	$ 11	$ (9)	$ (25)